EEs - X10 tripping ArcFault Breaker

[travelover]

I recently replaced my breaker box and to comply with the latest electrical code, I had to install a bunch of arc fault breakers. All is well, except one circuit. I have an X10 switch in one electrical box that can be actuated either directly or remotely, making it function like a 3 way switch. A second electrical box holds a regular switch (for a separate light) and the remote X10 actuator switch. I can turn on the light with the remote actuator switch with no issue if the other switch is off, but if the switch is on and I use the remote actuator switch, it trips the arc fault breaker. Both are on the same circuit. Prior to the arc fault breaker installation, all was good.

Some Googling turned up no answer, so I'm tossing it out to the EEs here who might have more insight.

 

[RobbieB]

Me thinks the X10 triac noise is tripping the breaker

 

[NW-Bound]

Yes.

But I do not follow the OP's wiring of 2 X10's in a 3-way arrangement, and with a manual switch in the mix.

 

[OldShooter]

There is a non-dimming Decora style X-10 switch that uses a relay not at triac. You could try one of those. They make a pretty good "clunk" sound when they switch, though.

Actually, what I would probably do is to replace the breaker with a standard one. Just because the manufacturers successfully lobbied the NEC doesn't mean that these new breakers are critical to civilization's survival.

 

[travelover]

There is a non-dimming Decora style X-10 switch that uses a relay not at triac. You could try one of those. They make a pretty good "clunk" sound when they switch, though.

Actually, what I would probably do is to replace the breaker with a standard one. Just because the manufacturers successfully lobbied the NEC doesn't mean that these new breakers are critical to civilization's survival.

I don't know what a triac is, but this is the device I have installed. It makes a thunk like a relay.


I can certainly swap out the arc fault breaker, but having $40 bucks in it, I'd like to get some value out of it if I can.

 

[travelover]

Yes.

But I do not follow the OP's wiring of 2 X10's in a 3-way arrangement, and with a manual switch in the mix.

The manual switch in the mix is incidental - for some reason the tripping occurs when this otherwise unrelated switch is on.

 

[RobbieB]

If it is a relay, there will be arcing. Maybe bad relay?

 

[Jerry1]

When I had that problem, there was a problem with the neutral. I’m no electrician but watching them try to figure it out was interesting. They kept saying everything tested out just fine, but every time I hit the switch, the breaker would trip. Finally, one guy said that the neutral was eff’d up, connected the wire better and all was well. Don’t know if that will help, but maybe double checking all the connections is in order?

 

[NW-Bound]

The manual switch in the mix is incidental - for some reason the tripping occurs when this otherwise unrelated switch is on.

What does that manual switch power, or is connected to?

It sounds like an extra load or capacitance on the Triac circuit changes the electrical noise characteristics, and that bothers the AFCI.

By the way, I have no experience with AFCI's, but have been studying this in order to have a safe installation of my DIY solar/storage system. DC arcing is A LOT worse than AC arcing.

Here's a video where a guy shows that his AFCI does not work at all.

 

[RobbieB]

Yeah, a bad neutral would make for more noise. Before 3 wire, neutral was ground and it really still is. If you measure any voltage between neutral and ground you have a problem.

 

[ERD50]

The manual switch in the mix is incidental - for some reason the tripping occurs when this otherwise unrelated switch is on.

But if they had to connect/re-connect the wiring to that switch, maybe something got miss-wired? Could that other switch be shorting out something when the X-10 is activated?

I'm not following the connection of that other switch though. Just a thought.

-ERD50

 

[travelover]

What does that manual switch power, or is connected to?

The manual switch controls two overhead lights - one is a 4 foot fluorescent with a ballast transformer and one is an LED bulb.

It sounds like an extra load or capacitance on the Triac circuit changes the electrical noise characteristics, and that bothers the AFCI.
............

Yea, I'd say so. I was hoping for a trick to make them compatible.

 

[NW-Bound]

OK. While we are on the subject of "electrical arcing" and the associated danger of fire, y'all may find the following interesting, and you do not even have to be an EE.

That is, DC arcing is a hell of a lot scarier than AC arcing, as this fellow demonstrates. He shows that 2.6kW circuit causes a hell of an arc with DC power. And I am building a 4.5kW solar system. Of course I have to be very very careful and have to know what I should know.

 

[NW-Bound]

... It sounds like an extra load or capacitance on the Triac circuit changes the electrical noise characteristics, and that bothers the AFCI.

The manual switch controls two overhead lights - one is a 4 foot fluorescent with a ballast transformer and one is an LED bulb.

Yea, I'd say so. I was hoping for a trick to make them compatible.

There might be some weird interference between the X10 triac and the LED bulb.

Do you remember ERD50's experience with a light dimmer (there's always a Triac in one) and an LED bulb that flickers until tamed with an incandescent in parallel?

You would need to look at the AC waveform with a scope. Or maybe a spectrum analyzer, as I understand that AFCI's look for a certain frequency characteristic to detect arc fault.

 

[Souschef]

I had a wired one some time ago. For no apparent reason, the monitor on my PC would blink off, then come back on.
I finally discovered the when DW turned off the ceiling fan in the bedroom which backs up to our office, it generated enough EMI to affect the monitor The light switch on the same circuit did not affect the monitor.

 

[HFWR]

According to the description, this x10 device is a relay/non-dimmable, so no triac...

 

[travelover]

But if they had to connect/re-connect the wiring to that switch, maybe something got miss-wired? Could that other switch be shorting out something when the X-10 is activated?

I'm not following the connection of that other switch though. Just a thought.

-ERD50

I changed out the breaker box with the help of an electrician. All we did was pull out wires from the old breaker box then reconnect them to the new box. The problem seems to be erratic - so maybe it is as simple as a bad connection.

 

[Telly]

OK. While we are on the subject of "electrical arcing" and the associated danger of fire, y'all may find the following interesting, and you do not even have to be an EE.

That is, DC arcing is a hell of a lot scarier than AC arcing, as this fellow demonstrates. He shows that 2.6kW circuit causes a hell of an arc with DC power. And I am building a 4.5kW solar system. Of course I have to be very very careful and have to know what I should know.

Back in the 1970s I needed to quickly design a 48 volt DC battery backup system for a system product. Batteries, equalizer charger, battery disconnect relay and controls including low voltage lockout and a system needs to shut down now trigger in advance of battery minimum.
There were some things that could be done to minimize arc on break, like magnetic blowouts, speeding up the rate of contact break by using a DPST relay and wiring the two contacts in series, effectively doubling the opening rate. Since then, I think there have been major advances in high-current contact metallurgy.

 

[gauss]

Back in the 1970s I needed to quickly design a 48 volt DC battery backup system for a system product. Batteries, equalizer charger, battery disconnect relay and controls including low voltage lockout and a system needs to shut down now trigger in advance of battery minimum.
There were some things that could be done to minimize arc on break, like magnetic blowouts, speeding up the rate of contact break by using a DPST relay and wiring the two contacts in series, effectively doubling the opening rate. Since then, I think there have been major advances in high-current contact metallurgy.

Wow! I thought that an inductive load (ie coils, motors etc.) was necessary to get the significant arcing shown in the video.

The heating coil load appears to be mostly resisitive (ie very small inductance).

I guess that I might need to retest for that 'EE' degree granted 30 years ago - or remember that I am not an electrician!

-gauss

 

[bjorn2bwild]

When an answer is not easily had, a little experimentation can often shed some light.

Progressing from more to less likely and easy to hard.....swap the LED light for incandescent, same with the fluorescent if practicable, swap the switch with another, ditto the breaker.

 

[travelover]

When an answer is not easily had, a little experimentation can often shed some light.

Progressing from more to less likely and easy to hard.....swap the LED light for incandescent, same with the fluorescent if practicable, swap the switch with another, ditto the breaker.

Good advice, of course. Since I don't understand exactly how an arc fault breaker works nor an X-10 remote, I was hoping there was an obvious interaction.

 

[homestead]

Travelover what triggered the need for new electrical box. Mine was installed in late 70's and is still working fine.

 

[travelover]

Travelover what triggered the need for new electrical box. Mine was installed in late 70's and is still working fine.

It was a Federal Pacific with Stab-Lok breakers. If you Google the topic, you'll see that they can be very dangerous because their testing data was falsified and sometimes they don't trip under a direct short.



https://www.washingtonpost.com/life...2c89fe3ca4c_story.html?utm_term=.59320be3aca1

 

[homestead]

It was a Federal Pacific with Stab-Lok breakers. If you Google the topic, you'll see that they can be very dangerous.



https://www.washingtonpost.com/life...2c89fe3ca4c_story.html?utm_term=.59320be3aca1

Yeah know what you mean, I helped replace one of those fire hazard boxes on my daughters house.

 

[NW-Bound]

I have not had an AFCI, and this makes me want to get one to experiment with. But I must resist, because I have enough now to keep busy on.

Back in the 1970s I needed to quickly design a 48 volt DC battery backup system for a system product. Batteries, equalizer charger, battery disconnect relay and controls including low voltage lockout and a system needs to shut down now trigger in advance of battery minimum.
There were some things that could be done to minimize arc on break, like magnetic blowouts, speeding up the rate of contact break by using a DPST relay and wiring the two contacts in series, effectively doubling the opening rate. Since then, I think there have been major advances in high-current contact metallurgy.

48V is not high enough to cause a serious problem. I am still trying to look up some numbers, but a few sources indicate that 80VDC is about the limit where serious consideration must be taken to safeguard against arc faults and associated fire hazard.

One can indeed design a breaker/switch to handle DC circuits, typically using magnets to deflect and suppress the arc, or a capacitor circuit to soften the current interruption, or using solid-state devices, etc...

The problem is when you have an unintentional wire break or loose connection in the circuit, or wire chafing, insulation breakdown, etc..., and not at an intended circuit break like a breaker or a switch where you can install protection measures and test for a safe operation. More on this later.